Guardians Prospect Adds Pitch Aiming to Outsmart Robot Umpire

The Cleveland Guardians might have found an unlikely early adopter of MLB’s next big technological leap. Right-hander Trenton Denholm, a four-year minor leaguer and Arizona Fall League standout, is already reshaping his entire approach on the mound to get ready for the automated ball-strike challenge system (ABS) coming to the big leagues in 2026.

He’s not just tweaking his pitches. Denholm is betting that innovation, not pedigree, will be his ticket to the show, from adding a knuckleball to fine-tuning a sinker.

How MLB’s ABS Era Is Changing Pitching Strategy

Major League Baseball’s upcoming automated ball-strike challenge system isn’t just a minor rules tweak. It’s a fundamental shift in how pitchers and hitters will attack the strike zone.

Under ABS, teams can challenge ball-strike calls in real time, with technology quickly confirming or overturning the ruling. That’s a huge change.

Denholm doesn’t see the change as a threat. For a pitcher who isn’t ranked among the Guardians’ top prospects, embracing ABS is a way to stand out in a crowded field.

Why the Strike Zone of the Future Favors Creativity

Traditional pitching always involved a cat-and-mouse game with umpires and hitters—trying to “expand” the zone with framing, deception, and command. With ABS, precise technology defines the margin for error, not human interpretation, so movement profiles, late life, and the ability to clip the edges of the zone suddenly matter more than ever.

That’s where Denholm’s creativity comes in.

Trenton Denholm’s Knuckleball Experiment

In an era dominated by high-velocity four-seam fastballs and sweeping sliders, Denholm has taken an unconventional route. He’s added a knuckleball to his repertoire.

It’s still a work in progress, but the early signs look promising. More importantly, it might be tailor-made for ABS conditions.

Pitching in the Arizona Fall League, a proving ground for rising talent, Denholm posted an impressive 2.13 ERA over 12 2/3 innings. While that line isn’t just about his newest pitch, it shows he’s competing effectively against some of the game’s better young hitters.

“Stealing Strikes” with a Knuckleball in the ABS System

Denholm thinks the unique, unpredictable movement of the knuckleball could actually play better under ABS than with a human umpire. He’s talked about the potential to “steal more strikes” with the knuckler, especially on the edges of the zone where the pitch might flutter late but still catch the plate.

Under traditional umpiring, a dramatic last-second dive might look wild and cost the pitcher a strike. Under ABS, if any part of the ball nicks the zone, it’s a strike—no matter how it looked.

So far, opponents haven’t challenged many calls against his knuckleball. That gives Denholm a valuable live-lab scenario to watch how hitters react and how the challenge system might be gamed in the future.

Adding a Sinker to Attack the Lower Zone

The knuckleball isn’t Denholm’s only adjustment for the ABS era. He’s also worked a sinker into his mix, aiming for the lower third of the zone and hoping to induce weak contact.

In an ABS landscape, a well-located sinker could be especially nasty. Pitchers who can consistently shave the bottom edge of the strike zone will force hitters into tough decisions: do you swing at borderline pitches you can’t drive, or risk letting a challenge-confirmed strike go by?

Crafting an Arsenal for the Edges

By pairing a knuckleball that dances unpredictably with a sinker that bores down and in, Denholm is building an arsenal designed to test the new system’s boundaries. It’s less about overpowering hitters and more about manipulating trajectory, vertical approach angle, and late movement in ways that make challenging pitches a risky proposition for batters.

That kind of forward-thinking approach could help a non-elite prospect stand out in camp.

Learning the Strategy of Challenges

Beyond the physical pitches, Denholm is studying the gamesmanship of the challenge system itself. When do you challenge? When do you trust the initial call?

He’s already experimenting with those decisions in the Fall League, using limited challenge opportunities to get a feel for the risk-reward balance on the mound. Denholm even joked about the idea of “challenging the challenge”, admitting how quickly the strategic layers could multiply once ABS becomes a staple of the big-league game.

Entertainment, Transparency, and Fewer Arguments

Denholm doesn’t just see ABS as a tactical tool. He sees it as an entertainment upgrade for fans. From his point of view, the system will:

For a sport constantly searching for ways to engage viewers, Denholm believes the ABS challenge system will bring a fresh layer of tension and excitement to every pitch.

More Than Metrics: Fall League Bonds and Big-League Dreams

While the numbers matter, Denholm says the Arizona Fall League is about more than statistics and experiments with new pitches. It’s also about the daily grind, the bus rides, and the relationships formed with peers all chasing the same dream.

He’s spent four years in the minors without the spotlight of top-prospect status, so he knows the importance of standing out not just with stuff, but with presence and professionalism. He values the camaraderie of the league as much as the competition, knowing that the way he carries himself is part of the evaluation.

Sending a Message Ahead of Spring Training

Spring training is coming up, and Denholm knows exactly what he wants. He’s got one goal: show the Cleveland Guardians he’s not just another backup arm.

He wants them to see a dedicated, resilient competitor who’s willing to adapt. Whether that means learning to throw a knuckleball, pounding the bottom of the zone with a sinker, or trying to keep up with all the new tech in baseball—he’s game for it.

With the ABS era possibly rewarding pitchers who get creative and take risks, Denholm’s not planning to get left behind. He’s hoping this is his shot to carve out a path to the majors.

 
Here is the source article for this story: Guardians prospect is adding a pitch he thinks could steal strikes from baseball’s new robot umpire